Can organs from people who had lethal injection be used?

Just something that popped into my head, in states that have lethal injection, can organs from people killed be used as donors for people who need them, or does the poison make it not possible?

I think that if the person is going to die anyways, it would be a good source of organs for those who need them, just so long as they found another way to kill them. I think a gunshot to the head would be more humane anyways, as I hear that lethal injection is supposedly actually painful. That may just be myth from movies though.

I’m also wondering, is it possible for someone to build up a resistance to it the same way as people do with other poisons or venoms?